Drum liners are used primarily to prevent product contamination in metal drums and other barrels containing products that are sensitive to deterioration. Drum liners are also installed in re-used metal drums to extend the useful life of the drum. Although several designs of drum liners exist in the art, it is believed that some specific requirements of the industry have not been properly addressed in the past by prior designs.
One specific example of a very demanding industry with regard to container-related product contamination is the transportation of maple syrup. Maple syrups are recognized by their respective flavour which is relatable by the experts, to the location of a maple grove and to the setting and maple species within that maple grove. Maple syrups are very sensitive to taste deterioration, and the simple contact of the product with an improperly painted metal surface for example, or with the lightly corroded metal of a container can deteriorate its flavour beyond usability. Plastic liners have been used in the past inside metal drums and common plastic barrels for storing and transporting maple products. However, there remain some concerns with these liners. For example, the syrup is known to adhere to the interior of the liner, and because of the structural arrangement of these liners, recovery can hardly be made. When a purchased batch of syrup is contained in several barrels, the lost of syrup remaining in the empty liners can be substantial.
Another concern with liners of the prior art is that generally, metal drums have bung holes of relatively small size through which some liners are installed. The relatively small sizes of theses bung holes represent certain limitations in the installation of a liner. These limitations are known to compromise the cleanliness and impermeability of a new liner during its installation inside a barrel.
Examples of prior art plastic liners for use in metal drums and plastic barrels are illustrated in the following patent applications and issued U.S. patents.
AU-B-15,127 filed by R. M. Matyja, and published Oct. 29, 1992; PA0 CA 2,061,161 filed by W. Lima et al., and published on Aug. 15, 1992; PA0 GB 2,228,725 filed by G. K. Bunschoten, and published on Sep. 5, 1990; PA0 U.S. Pat. No. 3,918,605 issued on Nov. 11, 1975 to C. J. Butler; PA0 U.S. Pat. No. 4,094,432 issued on Jun. 13, 1978 to S. Zilbert; PA0 U.S. Pat. No. 5,046,634 issued on Sep. 10, 1991 to G. P. McFarlin et al.; PA0 U.S. Pat. No. 5,154,307 issued on Oct. 13, 1992 to T. W. Hauk; PA0 U.S. Pat. No. 5,154,308 issued on Oct. 13, 1992 to D. A. Larson; PA0 U.S. Pat. No. 5,169,019 issued on Dec. 8, 1992 to B. Budenbender; PA0 U.S. Pat. No. 5,217,138 issued on Jun. 8, 1993 to D. E. Nichols; PA0 U.S. Pat. No. 5,222,620 issued on Jun. 29, 1993 to W. Lima et al.; PA0 U.S. Pat. No. 5,379,913 issued on Jan. 10, 1995 to T. M. Rieke et al.;
Because of the aforesaid concerns, basically, it is believed that there continues to be a need in the industry for a drum liner system which is mountable in a common metal drum, which allows for a sanitary installation of the liner therein and from which adhered product can be easily washed out and recovered.